Isabella married John Fitzalan of Clun and Oswestry, son of John Fitzalan Earl of Arundel, Lord of Clun and Oswestry and Maud (Matilda) de Botiller of Lincoln, before 14 May 1260.1556 (John Fitzalan of Clun and Oswestry was born on 14 Sep 1246 in Clun, Shropshire, England,1549,1557 died on 18 Mar 1272 in Arundel, Sussex, England 1549,1556 and was buried in Haughmond Abbey, Shropshire, England 1556.)